VCSEL-based optics have displaced electric cables today in supercomputers, but with power, density and cost requirements increasing exponentially as the systems get powerful, the need increases to move to on-chip optics.

Because a 10x increase in performance means the machine will consume double the power, to make future supercomputers feasible to build and to operate optics will need to be more widely used he said. In 2008 a 1-petaflop computer cost $150 million to build and consumes 2.5 MW of power. Using the same technology, by 2020 a 1 exaflop machine would cost $500 million to build and consume 20 MW of power.

Kash gave a timeline that would find optics replacing electrical backplanes by 2012 and replacing electrical printed circuit boards by 2016. In 2020, optics could be directly on the chip. In a less aggressive scenario, by 2020 all off-chip communications need to be optical, he said.

But for that to happen, to get optics up to millions of units in 2010, the price needs to drop to about $1 per Gb/s, he said. Today, Gb/s processing costs about $10.